test: add pixi build setup and run it in CI

.github/workflows/build.yml

@@ -0,0 +1,50 @@
+name: build.yml
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    types:
+      - labeled
+  workflow_dispatch:
+
+jobs:
+  build:
+    if: github.event_name == 'workflow_dispatch' || github.event.label.name == 'ci:pixi-build' || (github.event_name == 'push' && github.ref == 'refs/heads/main')
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+
+      - name: Set up Pixi
+        uses: prefix-dev/setup-pixi@main
+
+      - name: Build with Pixi with Pixi
+        run: pixi build
+
+      - name: Authenticate prefix.dev
+        run: pixi auth login https://prefix.dev --token ${{ secrets.PIXI_BUILD_TEST_CHANNEL_API_KEY }}
+
+      - name: Upload to prefix.dev
+        run: pixi upload https://prefix.dev/api/v1/upload/pixi-build-test pixi-*.conda
+
+      - name: Install from prefix.dev
+        shell: bash
+        run: |
+          #!/bin/bash
+          pixi_file=$(ls pixi-*.conda)
+          echo "pixi_file: $pixi_file"
+          spec=pixi=$(echo $pixi_file | cut -d- -f2)=$(echo $pixi_file | cut -d- -f3 | cut -d_ -f1)
+          echo "spec: $spec"
+          pixi global install --channel https://prefix.dev/pixi-build-test -e pixi-test --expose pixi-test=pixi $spec
+
+      - name: Test installed pixi
+        shell: bash
+        run: |
+          pixi-test --version
+          pixi-test --help
+          pixi-test global install bat
+          bat --version

.gitignore

@@ -10,3 +10,5 @@ site/
 .cache
 pytest-temp
 /vendor
+
+*.conda

pixi.toml

@@ -1,4 +1,4 @@
-[project]
+[workspace]
 authors = [
   "Wolf Vollprecht <wolf@prefix.dev>",
   "Bas Zalmstra <bas@prefix.dev>",
@@ -10,6 +10,7 @@ name = "pixi"
 # Using faster repodata fetching from our experimental fast channel, which implements https://github.com/conda/ceps/pull/75
 channels = ["https://prefix.dev/conda-forge"]
 platforms = ["linux-64", "win-64", "osx-64", "osx-arm64", "linux-aarch64"]
+preview = ["pixi-build"]
 requires-pixi = ">=0.45"
 
 [dependencies]
@@ -234,3 +235,27 @@ schema = { features = [
 ], no-default-feature = true, solve-group = "default" }
 test-export = { features = ["micromamba"], no-default-feature = true }
 trampoline = { features = ["trampoline"], no-default-feature = true }
+
+#
+# Package definition
+#
+
+[package]
+name = "pixi"
+version = "0.45.0"
+
+[package.build]
+backend = { name = "pixi-build-rust", version = "0.1.*" }
+channels = [
+  "https://repo.prefix.dev/pixi-build-backends",
+  "https://fast.prefix.dev/conda-forge",
+]
+
+[package.host-dependencies]
+rust = ">=1.86.0,<1.87"
+
+[package.target.linux-64.build-dependencies]
+clang = ">=20.1.2,<20.2"
+compilers = ">=1.6.0"
+make = ">=4.3,<5"
+mold = ">=2.33.0,<3.0"